A highly controlled psychodrama assembled in a brain-teasing way, “Unfinished Girl” reps an impressive feature debut by writer-director Cheng Er that deserves exposure at Asian-friendly fests. Headlined by a remarkable perf from actress Gao Yuanyuan (“Shanghai Dreams”) as a disturbed young woman who’s convinced her brother-in-law engineered her parents’ death years earlier, the pic largely avoids conventional thriller elements in favor of an almost Kammerspiel-like construction that generates its own emotional intensity. Released locally last October, the film has the feel of something fresh from the mainland Chinese industry.

Opening scenes set up the fractured timescale in which the essentially simple tale is told, creating an unreal atmosphere. Story proper begins with insurance adjuster He Wei (Xu Zheng) thinking he’s knocked a young girl down with his car. In fact, the girl fell off her own bike, but during a checkup it’s found she has the beginnings of a brain tumor. To help out the girl’s father financially, He offers to backdate a health insurance policy.

Meantime, He has been assiduously helping out Xiao Ke (Gao), the younger sister of his wife, Xiao Feng (Tao Hong), by finding her a job, an apartment and so on. Zonked out by the news that she’s terminally ill, Xiao Ke spends her days drifting around alone, unable to manage her own life.

Pic takes an explicit leap into psychodrama territory when, on one of his regular visits to her apartment, Xiao Ke suddenly knocks He out and tapes him to a chair. Convinced, from a series of chance events, that He was not only linked to her parents’ death but is also trying to speed up her own, she sets about torturing He.

Long flashbacks during the interrogation now fill in both present and past backstories, which have thus far been withheld from the viewer.

Film has an almost identical plot to that of last year’s “Sweet Revenge,” also mainland-set, helmed by Taiwan’s Ho Ping and starring Fan Bingbing, Nick Cheung and Anthony Wong. Cheng’s plotting is simpler but his structure much more playful, leading viewers early on into an extreme situation and then daring them to believe what they’re seeing.

The central confrontation between the bound-and-gagged He and the knife-wielding Xiao Ke has an almost legit flavor, played out in a neat, modern apartment and framed and lit as precisely as the rest of the movie. The drama comes not from whether He will manage to escape alive, but from why the seemingly barking-mad girl is terrorizing her caring brother-in-law.

Several long takes of characters’ monologues give the film a slightly arty feel, with both Gao and Xu responding well to the unblinking camera. At heart, the pic is still a genre movie with its fair share of leaps of logic, but does grip throughout its tight running time. An experienced thesp in her own right, Tao (“A Beautiful New World” is largely thrown away in the peripheral role of He’s loving wife.

Though nominally set in Shandong province, pic could take place anywhere among China’s modern high-rise cities. Discreet piano-and-strings score by Lin Hai mirrors d.p. Xu Wei’s visual precision.

Poor English title has no apparent meaning; Chinese one literally means “The Third Person.”